package editor.cn;

//At a lemonade stand, each lemonade costs $5. 
//
// Customers are standing in a queue to buy from you, and order one at a time (i
//n the order specified by bills). 
//
// Each customer will only buy one lemonade and pay with either a $5, $10, or $2
//0 bill. You must provide the correct change to each customer, so that the net tr
//ansaction is that the customer pays $5. 
//
// Note that you don't have any change in hand at first. 
//
// Return true if and only if you can provide every customer with correct change
//. 
//
// 
//
// 
// Example 1: 
//
// 
//Input: [5,5,5,10,20]
//Output: true
//Explanation: 
//From the first 3 customers, we collect three $5 bills in order.
//From the fourth customer, we collect a $10 bill and give back a $5.
//From the fifth customer, we give a $10 bill and a $5 bill.
//Since all customers got correct change, we output true.
// 
//
// 
// Example 2: 
//
// 
//Input: [5,5,10]
//Output: true
// 
//
// 
// Example 3: 
//
// 
//Input: [10,10]
//Output: false
// 
//
// 
// Example 4: 
//
// 
//Input: [5,5,10,10,20]
//Output: false
//Explanation: 
//From the first two customers in order, we collect two $5 bills.
//For the next two customers in order, we collect a $10 bill and give back a $5 
//bill.
//For the last customer, we can't give change of $15 back because we only have t
//wo $10 bills.
//Since not every customer received correct change, the answer is false.
// 
//
// 
//
// Note: 
//
// 
// 0 <= bills.length <= 10000 
// bills[i] will be either 5, 10, or 20. 
// 
// 
// 
// 
// 
// Related Topics 贪心算法 
// 👍 142 👎 0

public class LemonadeChange {
    public static void main(String[] args) {
        Solution solution = new LemonadeChange().new Solution();
        System.out.println(solution.lemonadeChange(new int[]{5, 5, 5, 5, 20, 20, 5, 5, 20, 5}));
    }

    //leetcode submit region begin(Prohibit modification and deletion)
    class Solution {
        public boolean lemonadeChange(int[] bills) {
            //记录面额张数
            int[] counts = new int[2];
            for (int i = 0; i < bills.length; i++) {
                int temp = bills[i] - 5;
                if (temp == 0) {
                    counts[0] += 1;
                } else if (temp == 5) {
                    //找五元，先判断是否有五元
                    if (counts[0] == 0) {
                        return false;
                    }
                    counts[0] -= 1;
                    counts[1] += 1;
                } else {
                    if (counts[0] > 0 && counts[1] > 0) {
                        counts[0] -= 1;
                        counts[1] -= 1;
                    } else if (counts[0] > 2) {
                        counts[0] -= 3;
                    } else {
                        return false;
                    }
                }
            }
            return true;
        }
    }
//leetcode submit region end(Prohibit modification and deletion)

}